Hydraulic underreamer



May 1, 1956 w. E. coYLE HYDRAULIC UNDERREAMER 2 Sheets-Sheet l Filed May8, 1955 INVENTOR TTORNEY WEoy Ze May 1, 1956 w. E. muiV 2,743,906

HYDRAULIC UNDERREAMER "Fi'l'ed VMay 8. 1953 v 2 Sheets-Sheet 2 'l' l I lI I I l', i l A l r' y I 53 INVENTOR Wooyze f l United States Patent2,743,906 HYDRAULIC UNDERREAMER William E. Coyle, Cotton Valley, La.Application May s, 1953, serial No. 353,304 4 claims.l (c1. ass- 74)This invention relates tol a hydraulic underreamer for enlarging a wellhole and ,has for its primary object to .provide a novel tool the reamervblades of which are opened by yhydraulic pressure and spring pressure.,

Another object of ythe invention is to provide a hydraulic underreamerhaving means for effectively supporting the blades and whereby the useof slots in a tool barrel through which the freel ends of the -bladesswing is eliminated, so that should the blades be bent by striking anobstruction the blades would still be able to resume a closed orinoperative position enabling the toolto be withdrawn from the wellhole.

Another object of the invention is.' to provide a tool which may bereadily adjusted to vary the opening pressure applied to the reamerblades depending upon the character of the hole to be rearned sothat agreater openalong a plane as indicatedv by the line 1 1 of Figure 2;

Figure 2 -is a longitudinalsectional view, partly in side elevation,taken substantially along planes as indicated lby the lines 2--2 ofFigures l and 3;

Figures 3, 4 and 5 are cross sectional views of the tool takensubstantially along planes as indicated by the lines 3-3, 4 4, and 55,respectively, Lfof Figure 2';

Figure 6 is a longitudinal sectional view taken substantially valong aplane as indicated by thev line 6-6 of Figure 4l;

Figure 7 is a side elevational view, vpartly in section, of -one elementofv the tool;

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'mounted a chok'e or llow restrictor 21. A sleeve 22 has Figure v8 is laside elevational view of one of the reamer v blades, and

Figure 9 iis yafsubstantially' centralsectional view of another elementfofthe tool.

Referring more specifically to the drawings, the novel underreamer toolin its entirety is designated generally 10 and includes a. body member,designatedgenerally 11, having an upper portion of substantiallylcylindrical cross section deii'ninga barrel -12'fand a lower' portionfrining a .fixedblade 1-3. v

The ybarrel 12 is provided with a` b'o're 14 the upper end'1'5 of whichis liared and internally threaded and adapted to be threadedly connectedto the lower end of a drill stem or pipe 16 by which'the tool issupported and rotated.

A piston 17 is 'reciprocably mounted in the upper por- 't'io'n'of thebore '14 and has a depending externally threaded boss I8. A cup-shapedresilientr ringorA washer 19 vlits around the 'upper portion ofvthepiston `17 and contacts 'the wall of the bore v14 to provide a sealbetween said a'n internally threaded upper end 23 which threadedlyengages the boss 18 for supporting said sleeve beneath the piston 17.The sleeve 22 is substantially smaller in diameter externally than thepiston 17 and extends slidably through an annular restriction or collar24 formed in the barrel 12 intermediate of the ends of the bore 14 andwhich collar forms a guide for the sleeve 22. Said internal collar orrestriction 24 is provided with a vkey 25 which slidably engages alongitudinally extending groove or keyway 26 formed in the outer side ofthe sleeve 22 and which opens outwardly of the lower end thereof. Therestriction 24 also forms a seat for the lower end of an expansion coilspring 27 which is disposed between the sleeve 22 and the wall of thebore 14 and the upper end of which bears against the underside of aportion of the piston 17 which is disposed above the upper end of thesleeve 22, for urging said piston and the sleeve upwardly in the barrel12.

A block 28 of circular cross section slidably ts in the` sleeve 22 andhas a pair of diametrically aligned screws y29 threadedly securedtherein and provided with circular vheads 30 which are'disposedexternally of the periphery of the block 28. Said screw heads 30slidably engage longitudinally extending slots 31 formed in said sleeve22 whereby the block 2S is prevented from turning in the sleeve 22 andlimited in its sliding movement longitudinally of said sleeve. Anexpansion coil spring 32 is disposed in the sleeve 22 between the lowerend of the boss 18 and the upper end of the block 2S for urging saidblock toward the lower end of the sleeve 22. The bottom portion of theblock 23 is provided with a downwardly opening recess 33 in which areloosely disposed the upper kends of a pair of connecting bars or links34. A pin 35 `pair of slots 37, the upper ends of which open intothelower end of the bore 14. Said slots 37 open outwardly of the lowerend of the barrel portion 36 and likewise extend radially in oppositedirections to open outwardly of substantially opposite portions of theperiphery of the lower barrel portion 36, as best illustrated in Figure3. The upper end of the blade 13 is suitably secured toor formedintegral with the lower barrel portion 36 and is disposed between andseparates the slots 37. Said blade 13 is of a width approximately equalto but no greater than the diameter of the barrel 12 and of a length toextend substantially below the barrel portion 36.

A pair of corresponding reamer blades 33 and 39 have rounded inner ends40 each provided with an opening 41. Said inner blade ends 4l) areloosely disposed in the slots 37. A headed pivot pin 42 extendsdiametrically through the barrel portion 36 and transversely through thevslots 37 and blade 13. Portions of the pivot pin 42 loosely engage nthe openings 41 for swingably mounting the blades 38 and 39. The pivotpin 42 has a restricted end 43' which is threadedly secured in thebarrel portion 36 and vtl'le head of said pivot pin 42, as seen inFigure l, is countersunk in the barrel portion 36. The pin 42 isretained in an applied position by a threaded plug 44 which threadedlytsinto a recess 45 inthe periphery of the barrel portion 36 and whichplug bears against the outer end of the piv'ot pin head. A headed screw46 is threaded and countersunk in the barrel portion 36 and has aportion seating in a recess 47 of the plug 44 to prevent the plug fromturning in the recess 45 until said retaining screw 46 is removed.

The inner blade ends di) have recessed remote sides i8 in whichoutwardly oiset lower ends of the links 34 loosely fit. Pivot elements1:-9 threadedly engage in the blade ends 40 and have outer endsextending into the recesses 48 and which are pivotally connected to thelower ends of the links 3d. Said pivot elements :i9 are offsetrelatively to the longitudinal centers or axes of the blades 3S and 39and to the openings 41 thereof, so that torque will be imparted to theblades by the links 34 when said links are displaced downwardly of thebarrel 12.

The blades 3S and 39 have corresponding outwardly tapered toothed edgesSi) and corresponding beveled and sharpened outer ends 51.

A pair of passages 52 are formed in the blade 13 and have upper endsopening into the bore 14 and outturned lower ends which open outwardlyof side edges of said blade 13 in advance of the blades 3b and 39. Thelower end of the blade 13 is split midway of its side edges and beveledon opposite sides of the blade adjacent its two side edges to form adrill bit 53. A pair of passages 5d extend longitudinally through theblade 13 and barrel portion 36 having upper ends opening into the bore14 and lower ends opening through the oppositely beveled faces of thedrill bit 53.

Assuming that the tool is attached to the lower end of the drill pipe16, the spring 27 will normally maintain the piston 17 in its positionof Figure l for retaining the reamer blades 33 and 39 in their retractedpositions of Figure l longitudinally of the body member 11 and againstopposite sides of the blade 13. the reamer blades 38 and 39 to operativeextended positions as illustrated in Figures 2 and 3, a circulating uid,not shown, is supplied under pressure to the upper end of the barrel 12from the drill pipe 1d. The bore of the restrictor or choke 21 is ofsufficiently restricted size so that the fluid will maintain a pressureon the piston 17 to force said piston and the sleeve 22 downwardly toits position of Figure 2 thereby compressing the spring 27. Should theformation around the body member 11 be relatively hard so that theblades 38 and 39 may not readily swing outward to their positions ofFigure 2, the block 28 will be forced upwardly in the sleeve 22 as saidsleeve slides downwardly with the piston 17, thus cornpressing thespring 32. Upward displacement of the block 28 in the sleeve 22 willreduce the area of the por- .v

tions of the slots 31 which communicate with the interior of the sleeve22 above the block 28 and, accordingly, the size of these ports fromwhich the circulation uid can escape from the sleeve 2" Thus, thecirculating fluid will exert a pressure on the blades 33 and 39 throughthe i block 28 and links 34 to urge the blades to extended positions.This pressure varies in ratio to the hardness of the formation in whichthe tool is disposed. Thus, as the tool 10 is rotated with the drillpipette the blades 33 and 39 will gradually swing outwardly to theirfully extended positions of Figure 2 under the pressure exerted by thecompressed spring 32 and by the circulating fluid each of which exerts adownward thrust on the block 28 and links 34 tending to force the blades33 and 39 to swing in opposite directions about the pivot d2. The amountof pressure exerted, tending to move the blades 33 and 39 to extendedpositions, may be varied by employing chokes having bores of differentdiameters and by employing springs 27 and 32 of different strengths. Thesharpened outer ends 51 enable the blades 38 and 3* to more readilypenetrate the formation surrounding the tool 10 so that the blades canassume the positions of Figure 2. The tool 10 is revolved clockwise asseen in Figure 3 and the extended blades 38 and 39 accomplish theirreaming operation by their toothed cutting edges Si) which are inclinedoutwardly and upwardly and thus tend to direct the cuttings of theblades outwardly and upwardly therefrom. Additionally, a portion of thecirculating fluid which passes through the choke 21 also passes underpressure through the passages 52 and is discharged radially therefrom inin order to move advance of the cutting edges 50 for washing away thecuttings.

The upwardly inclined toothed edges 50 will tend to cause the tool 10 torotate at a steady speed and to more accurately follow the pilot holeand said teeth will lessen the torque on the tool and cause it to cutmore rapidly. The cushioning spring 32 insures maintenance of a uniformpressure on the blades 33 and 39 so that an increase in pressure of thecirculated uid above the piston 17 will not produce an increased thrustthrough the links 34 on the blades. This pressure on the blades may bereadily varied by employing springs 32 of different tensions dependingupon the character of the formation to be reamed.

Should the blades be bent due to striking an obstruction, the bendthereof will be in a direction so that said blades may still be swungback to retracted positions and will merely be bent away from the fixedblade 13. Thus, closing of the blades will not thereby be prevented asfrequently occurs in underreamers the blades of which t a slottedportion of a tool body. The bit 53 will follow the pilot hole and willclear the same should it ll up in advance of the tool 10.

Various modifications and changes are contemplated and may obviously beresorted to, without departing from the spirit or scope of the inventionas hereinafter defined by the appended claims.

l claim as my invention:

l. A reaming tool comprising an elongated body member having an upperend detachably secured to the lower end of a drill pipe, said bodymember having a 'bore in the upper portion thereof communicating withthe drill pipe for receiving a circulating fluid under pressuretherefrom, a piston slidably mounted in the upper portion of said bore,a pair of reamer blades, means swingably connecting said reamer bladesadjacent inner ends thereof to the body member below the piston, meansincluding links connecting the blades to the piston for swinging theblades outwardly to radially extended positions when the piston isdisplaced downwardly, and spring means urging said piston toward theupper end of said bore for drawing said blades inwardly to retractedpositions longitudinally of the tool, said body member havingtransversely spaced slots disposed below the bore thereof and separatedfrom one another by a part of the body member, said slots having upperends opening into said bore and having other portions opening downwardlyfrom another part of the body member and radially outwardly thereof,said inner ends of the reamer blades and the lower ends of said linksbeing swingably disposed in said slots, and a stationary blade formingthe lower end of the body member and having an upper end disposedbetween the inner ends of said reamer blades and constituting said firstmentioned part of the body member, the outer ends of said reamer bladesstraddling an exposed lower portion of. the stationary blade when thereamer blades are in retracted positions.

2. A tool of the character described comprising a barrel having an upperend detachably connected to a drill pipe and provided with alongitudinal bore communicating with the drill pipe to receive acirculating uid under pressure therefrom, a piston slidably mounted inthe upper portion of said bore and urged downwardly by the pressure ofthe circulating fluid, a pair of reamer blades having inner endsdisposed in the lower end of said barrel, a partition having an upperend secured to the barrel and disposed in the lower end of said bore anddefining slots in which the inner ends of the reamer blades areswingably disposed, said slots opening downwardly and radially outwardof said barrel, a pivot'pin pivotally mounting the inner ends of thereamer blades in the barrel, a spring urging the piston upwardly in saidbarrel, said piston having a bore extending therethrough, a sleeve fixedto and depending from the piston and communicating with the bore thereofthrough which the circulating uid passes from above to `below thepiston, a block slidably disposed in and closing the lower portion ofsaid sleeve, said sleeve having a slot disposed between the piston andsaid block for escape of the circulating fluid from the sleeve into thebore of said barrel, means retaining said block slidably in the sleeve,a pair of links having complementary ends pivotally connected to theblock and opposite ends pivotally connected to the reamer blades atpoints spaced from the pivot pin, and a cushioning spring disposed inthe sleeve and bearing against and urging said block away from thepiston wherebythe blades are swung inwardly towards positions axially ofthe barrel when the piston is displaced upwardly by said spring andyieldably urged outwardly to extended positions substantially radiallyof the barrel when the piston is displaced downwardly, said block beingslidably movable in the sleeve toward the piston for compressing thecushioning spring and for restricting the slot of said sleeve forincreasing the pressure exerted on the links for urging the blades toextended positions.

3. A tool as in claim 2, a stationary blade forming a dependingextension of the partition, the outer ends of said reamer bladesstraddling said stationary blade when the reamer blades are in retractedpositions.

4. A tool of the character described comprising a barrel having an upperend detachably connected to a drill pipe and provided with alongitudinal bore communicating with the drill pipe to receive acirculating iluid under pressure therefrom, a piston slidably mounted inthe upper portion of said bore and urged downwardly by the pressure ofthe circulating fluid, said barrel having a recessed portion disposedbeneath and communicating with said bore, a pair of reamer blades havinginner ends disposed in said recessed portion of the barrel, a pivot pinpivotally mounting the inner ends of the reamer blades in the recessedportion of the barrel and in which the inner ends of the reamer bladesare swingably disposed, a spring urging the piston upwardly in saidbarrel, said piston having a bore extending therethrough, a sleeve fixedto and depending from the piston and communicating with the bore thereofthrough which the circulating uid passes from above to below the piston,a block slidably disposed in and closing the lower portion of saidsleeve, said sleeve having a slot disposed between the piston and saidblock for escape of the circulating fluid from the sleeve into the boreof said barrel, means retaining said block slidably in the sleeve, apair of links having complementary ends pivotally connected to the blockand opposite ends pivotally connected to the reamer blades at pointsspaced from the pivot pin, and a cushioning spring disposed in thesleeve and bearing against and urging said block away from the pistonwhereby the blades are swung inwardly towards positions axially of thebarrel when the piston is displaced upwardly by said spring andyieldably urged outwardly to extended positions substantially radiallyof the barrel when the piston is displaced downwardly, said block beingslidably movable in the sleeve toward the piston for compressing thecushioning spring and for restricting the slot of said sleeve forincreasing the pressure exerted on the links for urging the blades toextended positions.

References Cited in the le of this patent UNITED STATES PATENTS 786,137Moser c Mar. 28, 1905 1,857,616 Baker May 10, 1932 1,887,895 Sipe Nov.15, 1932 1,997,436 Seay Apr. 9, 1935 2,548,931 Baker Apr. 17, 19512,654,574 Kammerer Oct. 6, 1953 FOREIGN PATENTS 21,696 Great Britain1,901,

